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Urbanization Helps Some Tropical Butterfly Species but Harms Specialists

Joanna Lawrence
22nd August, 2016

A new study provides insight into how urbanization affects tropical butterfly species. Researchers studied butterflies in Singapore and found that while many of them are generalists, the specialist species are dependent on native flowers. As native plant species become rarer due to human activities, specialist butterflies may run out of food. The details are in a paper just published in the journal Biological Conservation. Researchers from the National University of Singapore analyzed data based on field observations at 62 locations in Singapore. During the three year study, the team recorded data on 190 butterfly species and 149 species of flowering plants. Most of the butterflies were generalists, feeding on nectar from a wide variety of flower species. 30 of the studied species, however, were specialists. These specialist butterflies preferred native species, though some of them adapted their diet when in urban environments. Other specialists were dependent on a single species of plant. The yellow vein lancer (Pyroneura latoia), for example, strongly prefers flowers from the native bandicoot berry plant (Leea indica). Interestingly, most of the specialist butterflies had more conspicuous wing patterns, suggesting that they specialized in order to develop more efficient feeding strategies. This would allow them to avoid predators that would likely notice them. As humans continue to develop land, non-native flower species tend to be planted. This benefits generalist butterfly species by providing them with more food sources. If non-native plants replace native flowers, however, specialist butterflies may struggle to find food. It’s unclear how much the changing landscape is affecting these species but at least a few learn to adapt when in urban areas, such as parks and gardens. The findings show that human influence may help generalist butterfly species while harming specialists. The authors suggest the conservation of native plant species to help specialist butterflies. The team is planning to conduct more studies in the future to better understand the impact of human landscaping on tropical butterflies. REFERENCE Anuj Jain et al. Flower specialization of butterflies and impacts of non-native flower use in a transformed tropical landscape. Biological Conservation (2016).